This week I have another puzzle for you to ponder over (just one this time, I promise!) I think I've heard of this puzzle before, but I read about it recently in Mathematics: A Very Short Introduction by Timothy Gowers and thought I would share.
The basic idea, is you have a chess board with two corners cut out like so:
You also have 31 dominoes that each cover two squares. Can you lie all of the dominoes on the chessboard, so they cover it completely?
Edit: Ok, it's not totally obvious from the picture, but the top left and bottom right squares have been cut out.